How Fire Engines Work

When a fire breaks out in a multi-story building, a ladder truck is used to get firefighters to the higher floors.

The ladder on the truck is raised and lowered using a hydraulic piston rod. As hydraulic fluid enters this piston rod through one of two hoses, the pressure of the fluid will either cause the rod to extend or retract. If the piston rod extends, the ladder will go up. If it retracts, the ladder will come down.

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Another set of hydraulic hoses allow the sections of the ladder to telescope up and down. A hydraulic motor is used to rotate the gear that moves the ladder from left to right. While the ladder is in use, four outriggers are extended to stabilize the truck.

One of the outriggers

On this 105-foot (32-m) ladder truck built by Pierce, the ladder also has a 3-inch pipe that runs the length of the ladder. This is an extra water line that is sometimes used to spray water on fires that are in a high spot, or to spray water down on a fire. This pipe can spray out 1,000 gallons per minute.

For large fires, or fires in high locations, the ladder truck has a line that can be raised 150 feet to attack a fire from above.

The ladder is controlled by a series of joysticks at the base of the ladder. The outriggers are controlled in the back of the truck. Each outrigger has four control levers: two for extending the beam out and two for lowering the leg to the ground. Metal pads are placed under the legs to prevent the force of the truck from cracking asphalt surfaces.